Skip to content
Snippets Groups Projects
Byron Lathi's avatar
opened issue #44 "Revive this project" at Byron Lathi / audio_qam
Byron Lathi's avatar
commented on issue #43 "Costas loop" at Byron Lathi / audio_qam

Downside of this is that the filters take a lot of cycles to actually start working:

Byron Lathi's avatar
commented on issue #43 "Costas loop" at Byron Lathi / audio_qam

Does m have to go from -M to M though? Or can it go from 0 to M? I don't see why not...

Byron Lathi's avatar
commented on issue #43 "Costas loop" at Byron Lathi / audio_qam

If we use the filter generated by FIIIR! then we need about 115 coefficients, which is kind of a lot. Either way, this means that to compute the co...

Byron Lathi's avatar
commented on issue #43 "Costas loop" at Byron Lathi / audio_qam

So I don't really want to use a moving average filter cause those kind of suck. But we need to somehow do a convolution per timestep?...

Byron Lathi's avatar
opened merge request !36 "Draft: Resolve "Costas loop"" at Byron Lathi / audio_qam
Byron Lathi's avatar
Byron Lathi's avatar
commented on issue #43 "Costas loop" at Byron Lathi / audio_qam

So in this case we need to have 2 NCOs but with the starting phase different. Since they receive the same error signal, the frequencies should alwa...

Byron Lathi's avatar
commented on issue #43 "Costas loop" at Byron Lathi / audio_qam

...

Byron Lathi's avatar
opened issue #43 "Costas loop" at Byron Lathi / audio_qam
Byron Lathi's avatar
deleted branch 42-nco at Byron Lathi / audio_qam
Byron Lathi's avatar
closed issue #42 "NCO" at Byron Lathi / audio_qam
Byron Lathi's avatar
accepted merge request !35 "Resolve "NCO"" at Byron Lathi / audio_qam
Byron Lathi's avatar
pushed to branch master at Byron Lathi / audio_qam
Byron Lathi's avatar
approved merge request !35 "Resolve "NCO"" at Byron Lathi / audio_qam
Byron Lathi's avatar
commented on issue #42 "NCO" at Byron Lathi / audio_qam

Even with a much lower symbol rate we still see a big error with even a small phase error, so we need to sync the clocks somehow. Lets try building...

Byron Lathi's avatar
pushed to branch 42-nco at Byron Lathi / audio_qam
Byron Lathi's avatar
commented on issue #42 "NCO" at Byron Lathi / audio_qam

...

Byron Lathi's avatar
commented on issue #42 "NCO" at Byron Lathi / audio_qam

This kinda works, but our feedback is not too great. We use a state machine based just on the sign. Can we do better than that?

Byron Lathi's avatar
pushed to branch 42-nco at Byron Lathi / audio_qam